


Oh Boy!

by Cylin



Category: X-Men: First Class (2011) - Fandom
Genre: Alternate Universe - Still Have Powers, Angst and Humor, Fluff and Crack, Genetics, Lab Rat AU!, M/M, PG-13 to NC-17 probably, and then some plot snuck in, lab rats, very very dodgy science
Language: English
Status: In-Progress
Published: 2013-05-15
Updated: 2013-06-03
Packaged: 2017-12-11 23:24:03
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 4,625
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/804436
Author URL: https://archiveofourown.org/users/Cylin/pseuds/Cylin
Summary: <blockquote class="userstuff">
              <p>Prompt Fill to this:<br/><i>I've seen plenty of AU's in which Erik is a shark, but WHY CAN'T WE HAVE SOMETHING ABOUT CHARLES BEING A LAB RAT? AN ACTUAL LAB RAT?</i></p><p>In another person's famous words: <strong>Yes, we can!</strong></p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> Shiromori is my hero!  
> The stuff he knows about _everything_ and the wonderful betaing he does.... I'm amazed every time! Thank you!  
>  (All remaining mistakes are mine. *manic glee* I spear them on tiny needles, put them in a display box and show them to ALL MY FRIENDS! *saunters off into the setting sun, display box and all*

The light-furred human – _light-haired_ , Chaharlsh reminded himself; that was what it was called in humans – had a tendency to give the rats names, whereas the darker furred one with the blue tinge – and here he stuck to calling it fur, because he had never seen a human with quite that much hair. Anyway, the blue-furred one only gave his subjects numbers.

Chaharlsh considered this highly insulting, especially because the numbers had nothing to do with the rat’s social order, and he didn’t understand what they signified. _Humans,_ he huffed indignantly.

Chaharlsh had observed the two humans quietly over the span of a couple of days after he had arrived in their laboratory, trying to gauge their character and ‘listening in’ to their minds. It was a bit confusing at first, because humans had an odd way of thinking anyway compared to the nicely logical way of rats and on top of that every individual human thought differently than the next. But with a bit of practice he managed very well.

Having been born in a lab in England, he had always been able to understand that human language, although they spoke it a little differently here.

Back in England, the lab technician caring for the rats had been heavily into Ethics, and Chaharlsh had found the concepts outlined in his books intellectually stimulating. But Chaharlsh thought the research Hank read was very interesting, too. Almost a little more interesting than Ethics. He liked listening in to Hank’s mind as he read.

 _Gene therapy: definitely an interesting concept._ Genetics seemed fascinating in general, and Chaharlsh absorbed the new knowledge eagerly.However, after a few weeks, he was getting desperately bored. He had picked the humans’ brains for any bit of interesting information on genetic research. Hank seemed to be the guy for that, whereas the other one, the light-haired one, Erik, was more interested in behavioural science, with mazes and puzzles. At least _he_ realised there was a highly sophisticated hierarchy amongst the rats, and he respected that.

Chaharlsh liked Erik. If he was pressed to choose between Hank’s brains and Erik’s passion for his work, his intellect would choose Hank, but his nose was definitely with Erik. Hank stank. There was this appalling miasma of sharp, prickly, chemical perfume that he dragged around with him and left in every space he occupied for more than a minute. It made Chaharlsh’s eyes water and numbed his nose. He didn’t like it at all!

Erik stank, too, but it was a natural human smell. It was definitely not pleasant, but at least he didn’t use any cologne or aftershave or the like when he was working with the rats. Chaharlsh felt Erik understood him and his fellows.

But after another few days, even the dreadful stench of Hank’s cologne was not enough to distract Chaharlsh from his brain-numbing boredom. Ever since being brought to this facility, he had been alone in his plastic cage – well fed and watered, and given every creature comfort a rat could hope for – but alone, tucked away amongst the other single-occupant tanks at the back of the lab. He felt quite alone a little self-pitying sitting in his plastic prison by himself. From the two humans’ minds, he knew and understood what quarantine meant, but this was solitary confinement! He was bored. Bored, bored, bored.

_Bo-oooooored!_

The light-haired one – Erik – looked in the direction of his plastic tank and Chaharlsh perked up, straining his whiskers forward, pressing his nose against the plastic. _Could I maybe walk through a maze now, please?_ They were tedious and ridiculously easy (especially because the human supervising the test _always_ thought about where they’d put the treats in the maze, and reading a human mind to find a treat was pup-level stuff), but he was so bored now, he felt like pulling his own fur out just to have something to do.

Chaharlsh had observed that quarantine was apparently considered over when Erik gave the rats their names, took their plastic prison from the back of the lab and carefully introduced them to a small number of other rats to form a new pack. And then the testing started, and that seemed quite exciting – or at least not as boring as sitting in a plastic prison by oneself.

Erik came over to his tank and looked in. Erik was big – very, very big from up close – but Chaharlsh was determined not be intimidated.

“Hank?” Erik called out without taking his eyes from Chaharlsh, “How long does this one have to remain in quarantine?”

Chaharlsh took a few shuffling steps to the side and looked over Erik’s shoulder, putting his front paws against the see-through plastic wall of the tank. Erik followed Chaharlsh’s gaze over his shoulder. Hank rustled through a few lists, reading. “It’s okay,” he said, putting his lists down again.

“Oh, good,” Erik murmured, turning back to Chaharlsh and adding to himself, “because this one looks like he’s going to have cabin fever soon.”

 _Oh, yes_ , Chaharlsh thought, _how right you are, human_.

“So, who are you going to be, then?” Erik asked as he took the small plastic cage from the shelf and carried it over to where his other lab rats sat waited. Erik was careful, but Chaharlsh was still grateful when the trip was over. He felt quite motion sick and had curled up in a corner, clinging to a ball of substrate he had gathered against his belly.

 _I’m not a Mr. Fibble, or a Chocolate, or a Fluffy!_ Chaharlsh thought indignantly.

“Hmm, you don’t peg me as a Mr Fibble, Chocolate or Fluffy,” Erik said, and Chaharlsh didn’t feel guilty at all for having influenced the human. “So, maybe Cheddar?”

 _You must be joking!_ Chaharlsh thought, appalled, letting go of his ball of substrate and forgetting his motion sickness instantly. _There’s something to be said for ‘you are what you eat’, but this is going too far_! He turned away from Erik, who was still looking inside his tank, and pointedly presented him with his broad, chocolate-coloured backside.

“Hmm, maybe not,” Erik mused.

 _Definitely not!_ Chaharlsh thought. _My name is Chaharlsh_ , he projected at Erik hard, looking over his shoulder, his small, dark eyes squinting slightly. _Cha-harlsh._

“Hmm, Shad?”

 _What? No!_ Chaharlsh brushed his paws over his whiskers frantically as if to dispel such a horrendous suggestion. _My mother named me Chaharlsh._

“Sherlock?”

_Flattering, but no! Cha-harlsh. Cha-haaaarlsh!_

“Chakotay.”

 _Oh, for goodness’ sake! Do I look like a space-faring Native American?_ He clamped both paws over his ears, pushing them against his head in resignation, looking at Erik reproachfully from under his brows. _Speak with me, slowly: Chaaaaaa-haaaaaarrrrrlsh!_

__

“Charles?”

_I give up. At least that’s reasonably close._

“You look like a Charles.”

 _I do not, but that’s okay. For you, I’ll be Charles_. Stupid humans and their inadequately equipped voice boxes. They weren’t even able to produce one tiny ultrasound by themselves. Chaharlsh – _Charles_ – wondered how they had managed to colonise the whole world, being so ill-equipped.

 

~*~

 

Erik looked at the small brown animal with something akin to fondness. He liked all his rats; that was why he gave them names in the first place, and he was devastated every time one of them died. But this one... This one was special. He could feel it. There was fierce intelligence in those small, shiny dark eyes that Erik found intriguing.

He had chosen to integrate Charles into a group of four young bucks – Leonardo, Donatello, Michelangelo and Raphael – he chuckled inwardly: _Maybe I should have called you Splinter._ – but something made him hesitate, and he felt he should listen to his gut instincts when it came to the animals.

He put Charles in a small compartment adjoining the bigger cage. A wall of wire netting was the only thing separating the two living areas. The netting could be removed once the rats were comfortable with each other, but for now it would be best if they could smell, hear and see each other, but not fight if they became territorial, and risk killing each other.

Charles was a little reluctant to leave his familiar plastic cage for the new surroundings, but when Erik made a low, soothing murmuring sound and thought of how much better this would be for the rat, Charles looked up at him and went without hesitation.

Erik lifted a brow. _That was odd._

The substrate was layered a little more thickly in the permanent cages, and Charles burrowed excitedly into it at once, his hind paws showering Erik’s lab coat with flecks of aspen shavings through the open door of the cage and the mesh of the wire netting. Charles’s nose was flecked with shavings when he finally emerged again, his whiskers quivering excitedly. Then he noticed the four rats standing on the other side of the netting and froze.

He sat on his haunches, letting his front paws rest on his belly. His whiskers strained forward. His nose quivered. His head was held high, and his back was tense and slightly hunched. There was a tension coming from him all of a sudden and the other four rats seemed to notice it, too, making small bubbling noises and grooming their fur thoroughly in an awkward frenzy of displacement activity.

“Oh hey, you’re a dominant one, aren’t you?” Erik muttered. Charles relaxed at once and turned his head towards him, nose twitching regally. Erik had a curious feeling about that in the pit of his stomach. It felt like Charles actually understood him. There was a nagging … something in the back of his mind. He stared, and Charles stared back unwaveringly. His eyes weren’t black, like Erik had initially thought. They were brown.

“Hey, Erik,” Hank called, and the moment was broken. “I’ve got to show you something.”

Erik closed the cage carefully, sparing a last glance for Charles, who had gone back to shifting the substrate around his cage. _Rats,_ Erik thought with a fond smile, but he was still feeling a little unnerved.

“It’s not one of your Youtube dna replication songs, is it?” Erik asked Hank as he turned around, fearing the worst.

“No,” Hank said with a frown, “and that was just that one time! Why do you keep bringing it up?”

“Because it really wasn’t funny, Hank.”

“ _I_ thought it was funny.” Hank said petulantly, which looked really odd on his blue face with the fangs and all.

“It really wasn’t,” Erik said without mercy.

“You just have no sense of humour, Erik,” Hank replied loftily. “Wonder if it’s genetic. I don’t envy you. How are you going to find a woman with no sense of humour? Did you know that most women tick ‘sense of humour’ as a point of attraction on the relationship surveys the psychologists have? Raven showed me.”

 _Yeah_ , Erik thought wryly, only that wasn’t really a problem for him. Women did not interest him. It wasn’t that women were _uninteresting_ or something - Erik was a little annoyed at the overemphasised political correctness going on inside his own head. Some of his best friends were women, but they just didn’t _do_ anything for him. Not in that way. Men on the other hand... _oh boy_.

“So what is it then, Hank?”

“Well, we kind of hit a snag,” Hank said dejectedly. “See this print out here? If you compare it with this...” He rummaged for a printout of another genetic analysis on his desk, spreading it over Erik’s chaotic desk. “It’s just not working.” Hank hunched his shoulders a little.

Erik could sympathise. He clapped his hand on Hank’s broad shoulder comfortingly.

“Man, I really want to lose this fur,” Hank muttered. “Be normal. Human.”

Erik frowned, half in annoyance and half in sympathy. This was an old argument between them. He could understand Hank very well. Hank’s mutation was definitely harder to bear than Erik’s own, and Erik appreciated the difficulties that it caused, but Erik had his own views on what was normal.

“Hank, we’re _not_ human. We’re mutants,” Erik said consolingly, and continued when Hank opened his mouth to protest, “but I know what this means to you, and we’ll find a way.” He squeezed Hank’s neck, smiling warmly.

Erik thought Hank was magnificent. He was an awesome looking guy, now. Erik had known him before his accident in the lab, and he had been very special even then. Only Erik and Raven knew that it hadn’t really been an accident at all. Erik could understand that Hank wanted to go back to looking the way he had before testing that stupid serum on himself. What Erik couldn’t understand was why Hank wanted to look completely human, to reshape his extraordinary feet as well. _Why become dull, when you could be exceptional?_

This was part of the experiments they did here: testing new gene therapies and how they affected behaviour, intelligence and lifespan. They really didn’t want to have a screw-up on their hands, because that was what Hank’s self testing had been – a very, very bad screw-up. They could loose their funding and their good reputations.

The lab rats that were in their cages now were part of the control group that would run the tests without having gotten any gene therapy. The rats the first round of gene therapy had been tested on would arrive back in the lab tomorrow, and although the printouts had already shown that the therapy was not quite right yet, they would need to run all the tests to have the whole series of tests remain uninterrupted.

Erik looked over at Charles’s cage and an amused smile broke out on his face.

The four rats were piled up in a tight ball on one side of the netting, as close to Charles as they could get, with Charles on the other side pressed close to the grille, almost as if the barrier between them did not exist.

 _Rats_ , Erik thought fondly, shaking his head.

 

xXx

 

If anyone would like to see the gem that is the youtube dna replication rap, you can find it here (<http://www.youtube.com/watch?v=Bju4C5GxeQs>)


	2. Chapter 2

Charles was pleased with his fellow bucks. They were four bright, young things, younger than him by four whole months which really made them pups in Charles’s eyes, but nice fellows. And on top of all of them naturally being reasonably telepathic, one was slightly telekinetic, which was always a plus.

Charles wondered if he could teach these youngsters to develop their latent talents. There wasn’t much Leonardo could move yet telekinetically besides the substrate, but maybe that was actually good for a beginning.

_Erik named these four very well_ , Charles thought, a little impressed with the human. Leonardo was indeed the leader of the four and devoted to learning how his telekinetic ability worked. Raphael was a little rough with a good heart, but a rather short temper. Michelangelo was curious and open-minded with a strong leaning towards the creative arts shuffling the wood chips in their cage in a decidedly arty fashion. Sometimes he was especially creative building little sculptures out of the substrate. Unfortunately humans seemed not to appreciate such art and it was destroyed every time the bedding in the cage was renewed. _Plebs! All of them! Well, maybe not Erik..._ Donatello was the brainiest of them all, a little like Charles himself, he noted proudly, and had apparently already grasped how the lock on their cage worked in theory, coaching Leonardo on the mechanics.

_Brilliant!_ Charles thought.

A week later Charles was bored again.  He and all the other rats of the first batch , the control group, had been running mazes and performing stupid lever tests. The tests had been interesting in the beginning; after all, you got a treat every time you manipulated the lever correctly, but after a while, it became boring. The treats were always the same. Charles understood that humans thought themselves culinarily superior, but _he_ , as a rat, had a sense of taste more refined than any human! And he only got yoghurt drops. The sugar made him feel oddly awake and whizzingly hyperactive as well. It would also make him fat, which was an attractive trait in a rat, but then he would feel like he had to shift more weight around, and he hated that.

Charles gave Erik a reproachful look, as Erik sat him down at the beginning of yet another maze. Erik just stood back with his clipboard and waited. Charles glowered, not moving an inch, but Erik looked so hopeful that it thawed Charles’s heart – and quickly. With a sigh and a bored twitch of his whiskers he started on his way, already having picked out the location of the treat in the maze from Erik’s mind. Hadn’t humans ever heard of a double-blind test? And they called themselves ‘ _scientists’_ …

As he wandered the meandering maze at a leisurely pace, Charles thought about how he could use this time to actually do something useful like train the youngsters. Leonardo would need all the training he could get (in the form of encouraging pep talks) if he ever wanted to move more than a fleck of substrate with his mind. They had discovered that he was good at moving fluids, though. They’d had a particularly successful session late last night in which Leonardo made a drop of water the size of his own head float lazily up inside their water bottle until it floated, self-contained, like a second surface at the upper end of the flask. Little drops had floated up behind it, like some upside down, eerily beautiful, slow-motion hourglass.

They had to stop their training however, when Hank started to rub his eyes and his gaze darted back and forth between the clock on the wall and the bubbling liquid in their flask. Erring on the side of caution, Charles called it a night when the vague question of possible sleep deprivation in Hank’s head coalesced into something more suspicious and he eyed their cage more attentively.

Charles and the others proceeded to innocently burrow around in the substrate for the rest of the evening.

It had actually been fun. Charles liked burrowing. And bruxing, oh yes, he liked that very much. He’d spent much of the night happily making the low burring sound to himself, feeling at peace with himself and the world.

But now he was stuck in this stupidly, mind-numbingly easy maze with a curious and expectant Erik watching his every move. Why did humans have to be so damn cute? Huge and lumbering in their size, smelling extraordinarily potent like... well, like humans, yes, but cute, nonetheless. It was hard to refuse them anything, just looking at them swaying around on their hind legs, so charmingly hairless, like new-born pups. Charles sighed. No, he couldn’t refuse Erik anything. How did he deserve this? Charles was made for greater things. At this rate his intellect would wither and die – probably of a sugar overdose…

However when he rounded the last corner of the maze, fully expecting to find that sugary yoghurt drop at the end of it, he was in for a surprise.

It wasn’t there.

Charles stopped, blinking perplexedly at the empty space. _What?_

He quickly checked back into Erik’s mind and found the exact image of a drop waiting for him right here, but there was none in sight.

“Huh,” said Erik, looking at Charles with raised eyebrows.

A sliver of cold panic shot through Charles. _Did the human know?_ Had Charles made a mistake and somehow given his mental presence away? Charles let his small pink tongue flick nervously around his two protruding incisors, wetting his furry lips, his whiskers vibrating with tension. He waited breathlessly for Erik’s next move, completely frozen in place.

Not knowing how to react to the potential of discovery, Charles suddenly felt the overwhelming urge to clean and comb his fur. In a frenzy of nervous displacement activity, he followed his urge, sitting back on his haunches and brushing his paws over his head soothingly. He always started with his head, and then craned his neck around so he could comb with his teeth over the longer, more bristly hair on his scruff and back until it shone, giving more order to the fur by sorting through it with his sharp-nailed paws. He took immense care in pawing over the soft fur on his head. He was rather proud of the way it was a tad longer than the other rats’. It definitely made him more attractive, he thought.

“Huh,” Charles heard from Erik again and stopped abruptly, pulled out of the comforting routine at once. _What am I doing?!_

Charles could smell him before he heard Erik’s voice, closer than before, and he slowly turned and looked at the human’s face.

Erik’s face was huge so upfront and personal as he leaned forward, but Charles was again determined not to feel intimidated. Erik smelled familiar and not threatening at all. His eyes looked at Charles curiously. They had an odd colour-variant, one Charles had only ever seen in humans. _Very, very light_ , he thought, _rather beautiful, with little flecks of even lighter colour around the black pupil_.

Feeling curious, he stepped closer, craning up his body, stretching to get closer to those eyes and that nose, because that seemed like a good place to start climbing. Charles was astonished at the sudden pull he felt towards this human. He wanted to climb all over him, maybe make a little nest from his hair.

With a jump, Charles was on him. His little nails dug into the collar of Erik’s lab coat hard, as Erik jerked back in surprise. Immediately he let his clipboard fall, pulling his hands up reflexively, cupping Charles gently in case he slipped and fell. Erik’s hands were wonderfully warm against Charles’s tail and the knobbly pads of his feet. They smelled of salty human skin. Charles liked salt – especially after having gotten such an overdose of sugar in the past couple of days – so he let his tongue flick out, collecting the salty residue of sweat from Erik’s palms.

He heard a warm, rumbling chuckle from underneath him, from deep in Erik’s chest. It vibrated through Charles’s feet, spreading through his body, and he felt very content. He ground his teeth against each other in lazy contentment.

“Hey there, little fella,” Erik rumbled lowly, “What are you up to, huh?”

_Getting closer to you_ , Charles thought unguarded, bruxing in bliss.

“What?” Erik breathed, his voice suddenly choked. Charles’s head snapped up at Erik’s tone, knowing immediately that he had made a huge mistake.

He made a quick sweep of his small paws over his own head, as if he was physically removing something. He brushed the memory of the past couple of seconds from Erik’s mind. Just like that, it was gone, and for the first time in his life Charles felt bad for having manipulated a human. _This_ human especially.

He rubbed his head once in apology against Erik’s palm.

 

~*~

 

Erik stared at the rat cupped gently in his hands. He had an odd feeling of negative déjà-vu, as if something hadn’t happened twice, but not happened at all. Charles looked up at him with his beady brown eyes, and Erik thought how sad he looked. “Hey there, little fella. What’re you up to?” As he said it, Erik had the vague feeling of repeating himself, but he was sure he hadn’t said anything before.

The rat just looked at him, his whiskers drooping a bit. One ear flicked once (it seemed almost apologetic) and then Charles curled up on himself in Erik’s palms, his pink tail wrapping around his round backside. Erik heard the whisper of a sigh come from him.

“Maybe that’s enough for you today,” Erik murmured gently so Hank wouldn’t hear him. In his first year of research, Erik had earned the scathing nickname ‘Rat-whisperer’ from the other scientists for talking to the lab rats. He knew they couldn’t understand him, of course. He had talked to them to feel less lonely when he spent hour after hour alone in the lab, the rats being the only other living creatures. After that first year, he made sure none of his colleagues saw him, but he never stopped talking to the animals. Erik preferred to think that they liked it, too.

He carefully carried Charles back to his cage, making sure on the way that his steps didn’t jolt the rat too much. He would have to mark this last test as inconclusive since the subject had jumped out of the test course straight at him. He had, for a moment, forgotten that rats could jump several times their body length. _Marvellous little creatures, rats_ , he thought, smiling at the curled-up furball in his hands.

When Erik tried to set Charles down on the soft bedding of the cage, Charles suddenly became very active again. He seemed reluctant to let go, digging his surprisingly sharp nails into the lines of Erik’s palms. Erik disentangled himself gently, making sure not to trap any of Charles’s nails or pinch his tail, but as soon as Charles was deposited on the substrate again, he made a small disapproving squeak and scuttled towards Erik’s hand with amazing speed and agility, climbing up his arm to his shoulder.  Erik tried to grab for him, but the small rodent managed expertly to free himself every time. Charles stopped only when he sat securely on the broad muscle spanning between Erik’s neck and shoulder.

Erik stood still in case of startling the animal. He could feel tiny exhalations of breath and ticklingly soft whiskers brushing the side of his throat as Charles sniffed his skin. A small paw was pushed against his neck, the nails pricking his skin slightly, as Charles followed his twitching nose up Erik’s neck and towards his ear. Goosebumps followed the soft sensations, spanning Erik’s whole back and giving him an odd feeling at the nape of his neck where his hair stood on end. His neck had always been exceptionally sensitive to touch.

He huffed once, grinning affectionately, turning his head slowly towards Charles. He had to crane his neck sharply to the side to see the brown rat.

Charles used the whorls of Erik’s ear to support his body weight further, grabbing the lower part of the antihelix and stretching up to Erik’s face, putting his paw right on the middle of Erik’s cheek. His whiskers tickled Erik’s cheek, as he leaned closer to Erik’s eye. He seemed to scrutinise the eye, closely, curiously looking into it. Erik entertained the idle thought that Charles might be looking through his eye directly into his head.

Erik knew that rats’ eyes weren’t in fact black, like they often appeared, but he was always astounded how sharp the black pupil could be distinguished from the brown of Charles’s iris. Erik's view was a bit blurred, because the rat was so close to his face, but he stared back at Charles with the same intensity with which the small creature regarded him. _Most curious behaviour for a rat_ , he thought. The thought was derailed as Charles leaned even closer and his long whiskers tangled with Erik’s eyelashes at the corner. Erik closed his eyes reflexively and chuckled lowly.

Charles retreated at once, snuffling softly. Erik fancied the idea that it was another small apology. As soon as he had the thought, Charles nibbled his earlobe affectionately and then strolled down Erik’s arm completely unhurriedly. With the utmost grace, he jumped the last distance back to his cage.

Erik smiled and closed the door.

xXx


End file.
